In recent years, energy and noise pollution problems have become more and more serious. A good solution to these problems would be to use electrical power driven vehicles, but development of electrical power driven vehicles has up to now been limited by the capacity of the batteries to achieve a larger moving range. Increasing the battery volume or quantity to increase the range will correspondingly increase the self-weight of the carrier, resulting in higher electrical energy consumption and does not meet economic requirements. Therefore, in the absence of a major breakthrough in solving the battery technical problems, a more practical driving method is to use combined driving structure designs. Current combined driving structure designs include:
(A) Series Combined Power Design: This design is the most typical structure for an electrically driven vehicle. In this design a generator is driven by the engine to generate electricity and charge the battery, after which the battery provides electricity to the driven motor to drive the vehicle. As the energy is converted several times, the overall efficiency of this design is low. An example of this design is the GM HX3 vehicle of General Motors. PA1 (B) Synchronized Power on Common Shaft Design: This design involves directly series combining the engine power output shaft and the rotating shaft of the driven motor, to thereby generate driving and speed controlling functions. An example of this design is West Germany's Volkswagen CHICO sedan.
For the case of the conventional engine and motor described in (B), only one of the engine and motor can be selected for output transmission, and the combination of their power output is not available.
In contrast, the disclosed distributed differential coupling combined power system of the invention permits the output power from the output shaft of an engine (or other rotational power source) to not only drive a front section load, but also to be combined with an electromagnetic coupling device to drive a rear section load. The electromagnetic coupling device is constituted by an AC or DC, brushed or brushless electric machine, and is a two-end structure. It includes a rotational field generating structure and a rotor, and the rotor shaft (or the field rotating shaft) is used as the output shaft to form an electromagnetic coupling device, while the other end is coupled with the engine output shaft through the transmission gear system. This design is capable of adding the power and speed of the engine output to the output generated by the electromagnetic coupling device itself to drive the rear load without being affected by the speed relationship between the two. In general, it has a smaller system volume and saves the cost and space in comparison with other combined power systems.